Heretofore in accordance with Leland F. Blatt U.S. Pat. No. 3,349,927, dated Oct. 31, 1967, there was provided a vacuum cup assembly having a body and a vacuum chamber in communication with the flexible vacuum cup together with a venturi jet assembly sealed within the body and connected to a source of pressurized air and to the vacuum chamber, and with the venturi jet assembly terminating in an air outlet in said body. Air escaping through the venturi produced a vacuum due to the Bernoulli principle, the vacuum being produced and held as long as the air flow is directed across the venturi for evacuating the vacuum chamber and the workpiece supporting flexible vacuum cup connected thereto. Should the vacuum producing air flow be stopped, a considerable period of time was necessary to allow atmospheric air to leak back through the venturi and pressurize the vacuum chamber in order that the workpiece may be separated from the vacuum cup.
Heretofore in the use of vacuum cup assemblies including the flow of pressurized air through a venturi jet assembly there have been employed air silencers such as disclosed in Leland F. Blatt U.S. Pat. No. 3,675,733 of July 11, 1972 and Leland F. Blatt U.S. Pat. No. 3,675,734 dated July 11, 1972.
The blow-off silencer essentially embodied a pair of hemispherically shaped opposed frequency distorters which modify certain frequency sound levels lowering them to a predetermined noise level for minimizing the noise of the exhausting air from the vacuum cup venturi assembly.